Deletion in Xp22.11: PTCHD1 is a candidate gene for X-linked intellectual disability with or without autism

Submicroscopic chromosomal anomalies play an important role in the aetiology of intellectual disability (ID) and have been shown to account for up to 10% of non-syndromic forms. We present a family with two affected boys compatible with X-linked inheritance of a phenotype of severe neurodevelopmental disorder co-segregating with a deletion in Xp22.11 exclusively containing the PTCHD1 gene. Although the exact function of this gene is unknown to date, the structural overlap of its encoded patched domain-containing protein 1, the transmembrane protein involved in the sonic hedgehog pathway, and its expression in human cortex and cerebellum as well as in mice and drosophila brain suggests a causative role of its nullisomy in the developmental phenotype of our family. Our findings support the recent notions that PTCHD1 may play a role in X-linked intellectual disability (XLID) and autism disorders.     

Development of vaccination strategies that elicit broadly neutralizing antibodies against human immunodeficiency virus type 1 in both the mucosal and systemic immune compartments

The antigenic diversity, rapid genetic integration into host cell DNA, and immune evasion tactics of human immunodeficiency virus type 1 (HIV-1) create formidable obstacles to the development of an effective vaccine against it. In spite of this, the advent of conformationally constrained HIV-1 Env and gp120 immunogens has made it feasible to formulate HIV-1 vaccines that induce broadly cross-reactive neutralizing antibodies and afford protection through humoral mechanisms. This paper reviews recent advances made by the authors toward the development of an HIV-1 vaccine that elicits such antibodies in both the mucosal and systemic immune compartments.     

Novel role of toll-like receptor 3 in hepatitis C-associated glomerulonephritis

Hepatitis C virus (HCV) infection is frequently complicated by glomerulonephritis with immune complexes containing viral RNA. We examined the potential influence of Toll-like receptors (TLRs), specifically TLR3 recognition of viral dsRNA exemplified by polyriboinosinic:polyribocytidylic acid [poly(I:C) RNA]. Normal human kidney stained positive for TLR3 on mesangial cells (MCs), vascular smooth muscle cells, and collecting duct epithelium. Cultured MCs have low TLR3 mRNA levels with predominant intracellular protein localization, which was increased by tumor necrosis factor-alpha, interleukin (IL)-1beta, interferon (IFN)-gamma, and the TLR3 ligand poly(I:C) RNA. Poly(I:C) RNA stimulation of MCs increased mRNA and protein synthesis of IL-6, IL-1beta, M-CSF, IL-8/CXCL8, RANTES/CCL5, MCP-1/CCL2, and ICAM-I; it also increased anti-proliferative and proapoptotic effects, the latter of which was decreased by inhibiting caspase-8. In microdissected glomeruli of normal and non-HCV membranoproliferative glomerulonephritis biopsies, TLR3 mRNA expression was low. In contrast TLR3 mRNA expression was significantly increased in hepatitis C-positive glomerulonephritis and was associated with enhanced mRNA for RANTES/CCL5 and MCP-1/CCL2. We hypothesize that immune complexes containing viral RNA activate mesangial TLR3 during HCV infection, thereby contributing to chemokine/cytokine release and effecting proliferation and apoptosis. Thus, TLR3 expression on renal cells, and especially MCs, may establish a link between viral infections and glomerular diseases.     

Human T-cell leukaemia virus in Africa: possible roles in health and disease

Observation of clustering of adult T-cell leukaemia/lymphoma (ATL) in the coastal areas of southern Japan led to speculations about its association with an environmental agent. Human T-cell lymphoma/leukaemia virus (HTLV) was later identified as the probable causal agent in these and similar cases of lymphoma/leukaemia, which were subsequently observed in first-generation West Indian Black emigrants living in England and the USA, in the forest areas of South America and in some south-eastern states of the USA. HTLV antibodies have also been identified in cases of malignant lymphoproliferative diseases (MLPD) in Ibadan and Zaria in Nigeria and in the sera of cancer patients from various parts of Africa, thus indicating that Africa is a major region for HTLV infection. Evidence is presented of the association of HTLV infection in Africa not only with T-cell but also B-cell neoplasia, such as Burkitt's lymphoma and chronic lymphocytic leukaemia (CLL). The prevalence rates of infection in normal blood donors appear to range from 3.7% in sub-Sahelian northern Nigeria to 10-15% in the south-western rain-forest area of Nigeria.     

Human T-cell leukemia-lymphoma virus type 1 and adult T-cell leukemia-lymphoma in Okinawa

A serological survey for the presence of antibodies against the human T-cell leukemia virus, type 1 (HTLV-1) in patients seen at the Chubu Hospital in Okinawa was undertaken. All patients with the clinicopathological diagnosis of adult T-cell leukemia-lymphoma were positive. These cases had the characteristic features of adult T-cell leukemia-lymphoma: diffuse histology, often mixed cell or pleomorphic, and a high frequency of hypercalcemia, leukemic phase, diffuse visceral involvement, and opportunistic infections. The median survival of these patients was short, being only 18 weeks. Of the other patients with cancers screened, two of five other non-Hodgkin's lymphoma patients were positive and three of eight patients with other hematological cancers were positive. In addition, three of the four immediate family members of one adult T-cell leukemia-lymphoma case had antibodies. Of the other persons (both in- and outpatients) without hematological cancers, those under the age of 50 had a much lower antibody prevalence (4%) than those over 50 (30%). There was no significant difference in antibody prevalence between the two sexes in either the younger or older age group. These findings further document that Okinawa is an endemic area for HTLV-1. None of the 157 individuals screened for antibodies to HTLV-3 were positive, consistent with the fact that no cases of the acquired immune deficiency syndrome have been reported from Okinawa.     

Trends in antiretroviral therapy and mother-infant transmission of HIV. The Women and Infants Transmission Study Group

Trends in the vertical transmission rate of HIV and evolving antiretroviral usage between 1990 and 1998 within the Women and Infants Transmission Study were evaluated. A decline in mother-infant transmission was temporally associated with advances in therapy, especially when regimens including a protease inhibitor were included in the analysis.     

Prevalence of antibodies to HTLV-I, -II, and -III in intravenous drug abusers from an AIDS endemic region

Antibody prevalences for human T-cell lymphotropic virus (HTLV) types I, II, and III were determined for 56 intravenous drug abusers from Queens, NY. While control serum samples lacked antibodies to all HTLV subgroups, seropositivity among drug users was 41% for HTLV-III, 18% for HTLV-II, and 9% for HTLV-I. Infection by HTLV-I and -II occurred independently of HTLV-III infection. Blacks had greater HTLV-III antibody prevalence than whites (54% vs 16%) and were more likely than whites to be seropositive for HTLV-I or -II (46% vs 11%). They exhibited a greater incidence than whites of double infection with HTLV-I or -II and HTLV-III (27% vs 0%), and 73% were seropositive for at least one of the viruses, compared with only 26% of the whites. The increased HTLV-I and -II infection seen in intravenous drug users suggests that once introduced into a population, these viruses may be transmitted by the same routes as HTLV-III. Transmission may have been restricted mainly to blacks in this study because of local drug use practices.     

Functional and phenotypic comparison of human T cell leukemia/lymphoma virus positive adult T cell leukemia with human T cell leukemia/lymphoma virus negative Sézary leukemia, and their distinction using anti-Tac. Monoclonal antibody identifying the human receptor for T cell growth factor.

Adult T cell leukemia (ATL) and Sézary leukemia are malignant proliferations of T lymphocytes that share similar cell morphology and clinical features. ATL is associated with HTLV (human T cell leukemia/lymphoma virus), a unique human type C retrovirus, whereas most patients with the Sézary syndrome do not have antibodies to this virus. Leukemic cells of both groups were of the T3, T4-positive, T8-negative phenotype. Despite the similar phenotype, HTLV-negative Sézary leukemic cells frequently functioned as helper cells, whereas some HTLV-positive ATL and HTLV-positive Sézary cells appeared to function as suppressors of immunoglobulin synthesis. One can distinguish the HTLV-positive from the HTLV-negative leukemias using a monoclonal antibody (anti-Tac) that appears to identify the human receptor for T cell growth factor (TCGF). Resting normal T cells and most HTLV-negative Sézary cells were Tac-negative, whereas all ATL cell populations were Tac-positive. The observation that ATL cells manifest TCGF receptors suggests the possibility that an abnormality of the TCGF-TCGF receptor system may partially explain the uncontrolled growth of these cells.